I'm new to chickens. I just got my baby chicks Thursday afternoon from a mail order hatchery. They are only a few days old and all seem very robust and happy in their brooder. A xl dog crate. There are 16 and they seem to have plenty of room for now. I plan to expand their brooder next week. But last night I had one chicken run around the edges frantically looking for a way out. She did this for quite some time. Then went into the mama heating pad cave and went to sleep. Well, today she is back at it. Frantically searching for a way out. Is this normal? I can't find any information about it.